Use of the meridian test for the detection of equine herpesvirus type 1 infection in horses with decreased performance

Objective - To evaluate use of the acupuncture meridian test for detection of recent or recently reactivated equine herpesvirus type 1 (EHV-1) infection in horses with decreased performance. Design - Case-control study. Animals - 40 horses. Procedure - Physical and neurologic examinations were performed, and acupuncture points on the bladder meridian were tested for sensitivity reactions in case and control horses. Polymerase chain reaction assays were performed to determine whether EHV-1 or equine herpesvirus type 4 (EHV-4) DNA could be detected in peripheral blood mononuclear cells. Complement fixation (CF) tests for detection of antibodies against EHV-1 and EHV-4 and virus neutralization (VN) tests for detection of antibodies against EHV-1 were performed on paired serum samples obtained 3 weeks apart. Results - There was a significant difference in skin sensitivity in the cervical, sacral, and gluteal regions and flank between case and control horses. By use of the meridian test, all case horses were sensitive to manipulation of all acupuncture points believed to be associated with EHV infections, whereas only a few control horses were sensitive at an occasional point. Equine herpesvirus type 1 or EHV-4 viremia was not detected in any horses. Mean ± SD VN antibody titers against EHV-1 were not significantly different between the 2 groups. Mean ± SD CF antibody titers against EHV-1 obtained 3 weeks after the initial samples were higher in case horses than control horses; however, unequivocal seroconversion was not detected. Conclusions and Clinical Relevance - Results of the meridian test in case horses were associated with sensitivity reactions similar to those detected by physical and neurologic examinations; however, an unequivocal association with EHV-1 or EHV-4 infection was not detected.